1. Field of the Invention
The present invention relates to fluorinated poly(arylene ether) compositions for use in coating microelectronic structures, such as integrated circuits, and the method for their manufacture. More particularly, this invention relates to the use of novel bisphenol reactants in the method of manufacturing novel poly(arylene ether) compositions which possess improved properties such as higher glass transition temperature and lower dielectric constant.
2. Background of the Invention
Fluorinated poly(arylene ethers) based upon decafluorobiphenyl have been used extensively as replacements for polyimides for use in spin-coating substrates, such as multichip modules, printed circuit boards, integrated circuits and other microelectronic devices in intermetal dielectric production. These fluorinated poly(arylene ethers), which are commercially available from AlliedSignal Inc. under the tradename xe2x80x9cFLARE(trademark)xe2x80x9d, not only exhibit a thermal stability comparable to that of polyimides but also possess about ten to forty times lower moisture absorption rate, a dielectric constant in the range of about 2.35 to about 2.65, and good retention of storage modulus above their glass transition temperature (xe2x80x9cTgxe2x80x9d). These properties are relevant not only to enhanced circuit performance, i.e. higher speed, lower power consumption, and reduced signal-to-noise ratios, but also to lower processing costs. By highly cross-linking these compounds with cross-linking agents or cross-linkable pendent groups, their performance may be enhanced under process integration conditions, i.e. a Tg increase to greater than about 300xc2x0 C. See Lau, A. N. K., et al., Am. Chem. Soc., Polymer Preprints, 33(1), 996-997 (1992).
Also well-known in the art are methods for synthesizing ethynylated biphenyl monomers such as 2,2xe2x80x2-bis(phenylethynyl)-5,5xe2x80x2-diaminobiphenyl by first producing 2,2xe2x80x2-diiodo-5,5xe2x80x2dimethoxybiphenyl from 3,3xe2x80x2-dimethoxybiphenyl. See Lindley, P. M., et al., in J. Polym. Sci., Part A: Polym. Chem., 1061-1071 (1991) and U.S. Pat. No. 4,683,340 to Lindley, et al. [together hereinafter referred to as xe2x80x9cLindleyxe2x80x9d]. However, the yield of ethylnylated aromatic compounds produced therefrom is very low, i.e. 4% to 14%.
It is further well known in the art to incorporate such ethynylated biphenyl monomers such as 2,2xe2x80x2-bis(phenylethynyl)-5,5xe2x80x2-diaminobiphenyl and 2,2xe2x80x2-bis(phenylethynyl)-5,5xe2x80x2-diaminobenzidine in the synthesis of high-temperature resistant, high-performance polyphenylquinoxalines and polybenzimidazoles. However, such methods are also laborious, costly, and low-yielding. See Lau, K. S. Y., xe2x80x9cChemistry, Characterization, and Processing of IMC Curing Polymers,xe2x80x9d Final Report, Air Force Contract F33615-79-C-5101, for period of September, 1979 to June, 1983, Hughes Aircraft Company (1983).
It would be desirable to provide an improved fluorinated poly(arylene ether) composition which would possess a Tg in excess of about 300xc2x0 C. without having to highly cross-link the compound or include cross-linkable pendent groups as well as without sacrificing any of the other properties associated with known fluorinated poly(arylene ether) compounds. It would also be desirable to provide an economical, high-yielding process for producing such compositions.
In accordance with this invention, there is provided a novel composition of Formula C: 
wherein
R is an aromatic nucleus which imparts a glass transition temperature of greater than 260xc2x0 C. to the composition;
m is an integer of from about 0 to about 50; and
n is an integer of from about 1 to about 200.
In accordance with another aspect of this invention, there is provided a process for manufacturing the above composition comprising:
reacting a compound of Formula A 
wherein
r is an integer of from about 0 to about 50,
or a compound of Formula D 
wherein
q is an integer of from about 0 to about 49,
with a compound of Formula B
HOxe2x80x94Rxe2x80x94OH 
wherein
R is an aromatic nucleus which imparts a glass transition temperature of greater than 260xc2x0 C. to the composition under conditions sufficient to produce the composition.
This invention is also directed to a process for producing a fluorinated poly(arylene ether) mixture suitable for spin-coating onto a substrate comprising:
a) forming a solution from a composition of Formula C 
wherein
R is an aromatic nucleus which imparts a glass transition temperature of greater than 260xc2x0 C. to the composition;
m is an integer of from about 0 to about 50; and
n is an integer of from about 1 to about 200
and an aprotic solvent; and
b) filtering the solution through at least one filter having a pore size of about 0.1 micrometers.
This invention is also directed to a process for producing a cured, coated substrate comprising:
a) forming a solution from a composition of Formula C 
wherein
R is an aromatic nucleus which imparts a glass transition temperature of greater than 260xc2x0 C. to the composition;
m is an integer of from about 0 to about 50; and
n is an integer of from about 1 to about 200;
and an aprotic solvent;
b) filtering the solution;
c) applying the solution of step b onto a substrate to form a film thereon; and
d) heating the film of step c under conditions sufficient to cure the film.
Another embodiment of the invention is directed to a process for making ethynylated, hydroxy-substituted biphenyl compounds comprising:
a) halogenating 3,3xe2x80x2-dimethoxybiphenyl under conditions sufficient to form 2,2xe2x80x2-dihalo-5,5xe2x80x2-dimethoxybiphenyl;
b) reacting said 2,2xe2x80x2dihalo-5,5xe2x80x2-dimethoxybiphenyl with a bromide containing compound in a chlorinated solvent under conditions sufficient to form 2,2xe2x80x2-dihalo-5,5xe2x80x2-dihydroxybiphenyl;
c) reacting said 2,2xe2x80x2-dihalo-5,5xe2x80x2-dihydroxybiphenyl with a hydroxyl-containing compound in the presence of a protection catalyst under conditions sufficient to form 2,2xe2x80x2-dihalo-5,5xe2x80x2-bis(tetrahydropyranoxy)biphenyl;
d) ethynylating said 2,2xe2x80x2-dihalo-5,5xe2x80x2-bis(tetrahydropyranoxy)biphenyl with a compound of the formula
CuCxe2x89xa1CRxe2x80x2
wherein Rxe2x80x2 is comprised of an alkyl group having from about 1 to about 20 carbon atoms, an alkenyl group having from about 1 to about 20 carbon atoms, an aryl group, a heteroaryl group, and derivatives or mixtures thereof to form 2,2xe2x80x2-bis(Cxe2x89xa1CRxe2x80x2)-5,5xe2x80x2-bis(tetrahydropyranoxy)biphenyl; and
e) hydrolyzing said 2,2xe2x80x2-bis(Cxe2x89xa1CRxe2x80x2)-5,5xe2x80x2-bis(tetrahydropyranoxy)biphenyl under conditions sufficient to form 2,2xe2x80x2-bis(Cxe2x89xa1CRxe2x80x2)-5,5xe2x80x2-bis(dihydroxy)biphenyl, wherein Rxe2x80x2 is as described in step d.
The poly(arylene ether) compositions of this invention not only possess a Tg in excess of about 350xc2x0 C. without having to highly cross-link the compound or include cross-linkable pendent groups thereto as well as without sacrificing any of its other properties such as solubility, spin-coatability, high thermal stability, low moisture absorptivity, low dielectric constant, and planarizability.